Several techniques and systems have been developed for stabilizing and correcting deformities in the spinal column and for facilitating fusion at various levels of the spine. Most of these techniques involve the disposition of a pair of longitudinal elements along opposite sides of the posterior spinal column. The longitudinal elements are engaged to various vertebrae by way of a number of fixation elements to thereby apply stabilizing and corrective forces to the spine.
Typically, the longitudinal element is either a semi-flexible rod or a rigid plate, each having a length sized to span the distance between at least two adjacent vertebrae. A wide variety of fixation elements can be provided which are configured to engage specific portions of a vertebra and connect to a corresponding longitudinal element. For example, one such fixation element is a hook that is configured to engage the laminae of the vertebra. Other prevalent fixation elements include spinal screws or bolts that have a threaded section configured to be anchored in vertebral bone.
If a spinal rod is employed, a series of connector devices are typically used to interconnect the rod to the fixation elements. The connector devices typically have a first opening adapted to receive and engage an upper portion of the fixation element, and a second opening adapted to receive and engage the rod. An example of such a system is the TSRH.RTM. Spinal System manufactured and sold by Medtronic Sofamor Danek Group, Inc., the Assignee of the subject application. The TSRH.RTM. System includes elongated rods and a variety of hooks, screws and bolts, all configured to create a segmental construct along the spinal column. If a spinal plate is used as the longitudinal element, the plate typically includes a series of openings or slots, through which extends an upper threaded portion of each fixation element. A nut is threaded onto each threaded portion to connect the spinal plate to the fixation elements. An example of such a system is disclosed in U.S. Pat. No. 5,728,097 to Mathews.
The assembly, delivery and manipulation of the implant components described above can be awkward or cumbersome due to the limited amount space available to manipulate the implant components and the required surgical instruments. Additionally, if the openings in the connector devices or spinal plates are not properly aligned with the corresponding upper portions of the fixation elements, considerable force may be required to stress the rod or plate to achieve the alignment necessary to engage the rod or plate to the fixation elements. Moreover, the assembly and manipulation of multiple implant components within the surgical site is tedious and time consuming, thus prolonging the surgical procedure and increasing the risks associated therewith. There is also a risk of mishandling the implant during delivery to the surgical site and possibly dropping the implant within the surgical wound.
There is therefore a general need in the industry to provide surgical instrumentation an techniques for advancing and guiding an implant or implant construct from a location outside of the body to a location adjacent the surgical site. The present invention meets this need and provides other benefits and advantages in a novel and unobvious manner.